Cell Relay Archive

[Thomas Frieling <thomas.frieling@experteach.de>]

In article <Twmd5.2767$J7.30018@grover.nit.gwu.edu>,
  <agallo@foghorn.nit.gwu.edu> wrote:
>
> Question about Synchronous residual Time Stamp (SRTS): is it required for
> implementing ATM over DS-3?  I have a microwave based DS-3 connecting two
> Marconi (FORE) 200BXs.  One side is receiving framing errors, the other side
> is relatively clean.  The radio vendor (Nortel) is claiming that SRTS will be
> required to make this link work.  The switch vendor agrees that it may solve
> the problem, but it is not required by the ATM Forum and customer demand
> for this feature is almost non-existant on native (non CES) DS-3.
>
> I can't find info abour SRTS on the ATMF approved specs or spec watch page.
> (...)

Hello,

do you really mean ATM over DS-3? SRTS is just a means to convey clocking
information from one application using AAL1 to the opposite side of the
virtual connection. I can't imagine how this can have any influence on
the error rate of the links the cells cross.
I'm not a radio link expert (never seen such a device in my life) but I
suppose the clock settings there might be faulty. My educated and
hopefully not to wild guess is: set the DS3 interface of ASX#1 to MASTER
(internal) and #2 to SLAVE (network). Set the cable side of transmitter
#1 to SLAVE, the radio side to MASTER and vice versa at #2.
In case you talk about a circuit emulation DS3 over ATM, SRTS is said to
improve the timing properties. It will minimize wander. Buffer underflows
on one side might cause a syndrome like framing errors. In this case try
to increase the size of the cell buffer on that side and here, too, check
for proper clock settings.

Thomas Frieling

(My opinions do not necessarily match those of my employer.)


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